Straightening installation for elongated circular articles

ABSTRACT

The straightening installation is provided with straightening rolls and centering rollers with the straightening rolls having contact surfaces for contacting the work between which cylindrical grooves are formed for enabling the straightening rolls to be moved together until defining a minimum clearance therebetween. Disposed in these grooves are centering rollers having a radius less than the depth of the grooves.

United States Patent 1 Semenenko et al.

I [451 -Mar. 5, 1974 STRAIGHTENING INSTALLATION FOR ELONGATED CIRCULAR ARTICLES [76] Inventors: Jury Lukich Semenenko, ulitsa Gogolya, 1, kv. 30; Nikolai Vasilievich Tumanov, ulitsa Simferopolskaya, 19, kv. 5; Leonid Mikhailovich Varava, prospekt Gagarina, 161, kv. 23, all of Dnepropetrovsk, U.S.S.R.

22 Filed: June 10,1971

21 Appl.No.: 151,711

[52] US. Cl. 72/78, 140/147 [51] Int. Cl BZlf 1/02 [58] Field of Search..... 72/78, 98 99,118, 119, 77,

[56] References Cited UNITED STATES PATENTS Didden 72/95 192,460 6/1877 Seaman 72/250 2,670,781 3/1954 Brofelth 72/95 427,288 5/1890 Allderdice 72/104 2,829,698 4/1958 Stikeleather 72/78 1,399,687 12/1921 Canda r 72/98 3,625,263 12/1971 Koplzynski 140/147 Primary ExaminerLowell A. Larson Attorney, Agent, or Firm-l-lo1man &Stem

[5 7] ABSTRACT The straightening installation is provided with straightening rolls and centering rollers with the straightening rolls having contact surfaces for contacting the work between which cylindrical grooves are formed for enabling the straightening rolls to be moved together until defining a minimum clearance therebetween. Disposed in these grooves are centering rollers having a radius less than the depth of the grooves.

2 Claims, 2 Drawing Figures PATENTEI] 5 74 FIE I FIG. .2

STRAIGI-ITENING INSTALLATION FOR ELONGATED CIRCULAR ARTICLES BACKGROUND OF THE INVENTION The present invention relates to equipment for metal working by pressure, and more specifically to installations for straightening elongated circular articles, for example, tubes, rods, etc.

This invention can most successfully be employed in the metallurgical industry, to produce tubes and rods as accurate blanks with a high degree of linearity, as well as in industries using strictly linear tubes and rods, for precision straightening of circular-shaped blanks. It can equally be employed as a separate installation, or as one incorporated in a production line for manufacturing circular tubes or rods by drawing and finishing (including straightening).

PRIOR ART Widely known at present are tube or rod straightening installations consisting of a horizontal frame which rotates in supports and comprises straightening sleeves or rolls. In these installations, tubes or rods of comparatively large diameters are straightened with a low accuracy, since no rollers are used therein to center the work.

Such installations were improved in that besides the straightening rolls, mounted in the rotating frame were blank centering rollers (see, for example, a US. Pat. No. 2,829,698 cl. 72-78). These installations enable straightening blanks of somewhat smaller diameter, and with higher accuracy.

However, these installations cannot be employed with blanks of rather small diameter, since the value of the minimum gap between the straightening rolls and the centering rollers is limited by the impossibility of mutually approaching these rolls and rollers until their contact.

When blanks of wide assortment, including those of quite small diameter, are to be straightened in these installations, their straightening rolls and centering rollers must be replaced, which requires an increased stock of the straightening tools. Besides, these installations do not feature high quality of straightening be cause of a comparatively small number of elasto-plastic deflections of the blank, which is due to the short length of the zone of plastic deformation within the straightening space.

An object of the present invention is to eliminate the aforementioned disadvantages.

Another object of the invention is to provide a straightening installation for elongated circular articles, which permits straightening a wide variety of articles, including those with a very small diameter, without any replacement of the straightening rolls and the centering rollers.

A further object of the invention is to provide an installation, which substantially raises the accuracy of straightening.

SUMMARY OF THE INVENTION With these and other objects in view, in an installation for straightening circular-shaped articles of any small diameter comprising a rotatable horizontal frame; supports in which said frame rotates; straightening rolls mounted on said frame, defining a straightening die, said straightening rolls having contact surfaces adapted to contact an article to be straightened; in the course of straightening, said straightening rolls being arranged so that the contact surfaces of one straightening roll are disposed between two contact surfaces of the other straightening roll, the straightening rolls being capable of being brought together until the rolls come into contact with each other; cylindrical grooves provided on said straightening rolls, said grooves being located coaxially with the straightening rolls between the contact surfaces of said rolls; and rollers to center the article, said rollers being disposed in said grooves, and having a radius less than the depth of the grooves.

Such a design makes it possible to straighten articles of very small diameters, and substantially raises the accuracy of straightening by significantly extending the length of the zone of plastic deformation within the space of straightening, due to which the number of elasto-plastic deflections of the article in the course of straightening is greatly increased.

For a better appreciation of the invention considered below is a particular illustrative embodiment thereof with references to the appended drawings, wherein:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a view of the installation according to the invention, partly in elevation and partly in longitudinal section;

FIG. 2 is a view partly in transverse cross section and partly in elevation.

DETAILED DESCRIPTION OF THE INVENTION The installation comprises supports I and 2 (FIG. I) in which a frame 3 rotates, and in which frame are mounted convex and concave straightening rolls 4 and 5, respectively. These rolls have surfaces 6 contacting an article 7 to be straightened, for example, a tube, which is fed into the straightening space through a guide sleeve 8. Provided between the surfaces 6 are cylindrical grooves 9 in which are disposed centering rollers I0 (FIG.2) having a radius smaller than the depth of the grooves 9. These grooves permit the straightening rolls 4 and 5 to be moved together until a minimum gap exists therebetween, which provides for straightening articles of any small diameter.

The rolls 10 are mounted in bifurcated supports 11 having threaded tails 12 which are inserted into guide sleeves I3. Nuts 14 are threaded onto the tails for serving to adjust the gap between the centering rollers 10. The supports 11 have damping springs IS.

The straightening rolls 4 and 5 (FIG.I) are mounted in bearings 16 in bifurcated supports 17, to which are welded hollow tail pieces 18. There are positioned on these tail pieces, through keys I9, rotary bushings 20 serving to regulate the angle of turn of the supports 17. The supports 17, and hence, the rolls 4 and 5 as well, are fixed in place by pins 21 extending through flanges 22 of the bushings 20.

The tail pieces 18 have a thread on which are threaded nuts 23 serving to adjust the gap between the rolls 4 and 5.

The frame 3 is mounted in the supports 1 and 2 by means of hollow trunnions 24 and 25, a pulley 27 is secured to the trunnion 24 by a key 26 and the pulley receives a V-belt of a drive serving to rotate the frame 3.

The installation functions as follows:

Before straightening an article of a given diameter, the required gap between the straightening rolls 4 and 5 is set by turning the adjustment nuts 23, and the required gap between the centering rollers is obtained by rotating the adjustment nuts 14.

By turning the regulating bushings 20, the straightening rolls-4 and 5 are set at the required angle to the axis of the article 7. During the operation of the straightening installation, the article 7 (tube, rod, etc.) is fed through one of the guide sleeves 8 into the straightening space defined by the rolls 4 and 5, and. emerges through the other guide sleeve 8.

Within the straightening space, the article to be straightened is loaded with forces transmitted by the contact surfaces 6 of the convex roll 4, and rests on the contact surfaces 6 of the concave roll 5 on which reactive forces are produced. it will be seen that when straightening, the contact surfaces are arranged so that the contact surfaces of one straightening roll are disposed between two contact surfaces of the other straightening roll. As a result, in the process of straightening, the article is subject to deflection by two couples of forces generating between the contact surfaces 6 of roll 4, a section of pure deflection with a permanent value of the bending moment, which significantly extends the length of the zone of plastic deformation within the space of straightening, and permits materially increasing the number of alternating elasto-plastic deflections of the article. Such a loading pattern enables the accuracy of straightening to be tangibly raised as compared to that secured by the conventional machines.

Effcctiveness of the proposed installation was proved by specimen testing, when stainless steel pipes with a diameter of down to 8 mm and a wall thickness of down to 0.6 mm were subject to straightening. These pipes which, prior to straightening, had a curvature of up to 20 mm per linear meter, after the straightening, featured a curvature of no more than 0.7 mm per meter of length.

Subjected to hot test straightening were also molybdenum alloy pipes with a diameter of down to 6 mm. The pipe curvature was up to l0 mm per linear meter, and after straightening it was reduced to 0.5 mm.

What we claim is:

1. An installation for straightening elongated circular-shaped articles of any small diameter, comprising a rotatable horizontal frame; supports in which said frame rotates; straightening rolls mounted on said frame, defining a straightening die, said straightening rolls having contact surfaces adapted to contact an article to be straightened; in the course of straightening, said straightening rolls being arranged so that the contact surfaces of one straightening roll are disposed between two contact surfaces of the other straightening roll, the straightening rolls being capable of being just the gap between the rollers. 

1. An installation for straightening elongated circular-shaped articles of any small diameter, comprising a rotatable horizontal frame; supports in which said frame rotates; straightening rolls mounted on said frame, defining a straightening die, said straightening rolls having contact surfaces adapted to contact an article to be straightened; in the course of straightening, said straightening rolls being arranged so that the contact surfaces of one straightening roll are disposed between two contact surfaces of the other straightening roll, the straightening rolls being capable of being brought together until the rolls come in to contact with each other; cylindrical grooves provided on said straightening rolls, said grooves being located coaxially with the straightening rolls between the contact surfaces of said rolls; and rollers to center the article, said rollers being disposed in said grooves, and having a radius less than the depth of the grooves.
 2. The straightening installation as claimed in claim 1 including means operably related to each roller to adjust the gap between the rollers. 